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For linearity, check cosine of angle instead of angle

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This commit is contained in:
Grant Sanderson
2023-01-17 13:16:58 -08:00
parent b16f0981f6
commit 1b3bc7a27c
1 changed files with 7 additions and 6 deletions
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13
manimlib/shaders/quadratic_bezier_stroke/geom.glsl
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@ -29,8 +29,10 @@ const int AUTO_JOINT = 1;
const int BEVEL_JOINT = 2;
const int MITER_JOINT = 3;
const float PI = 3.141592653;
const float ANGLE_THRESHOLD = 1e-3;
// When the cosine of the angle between
// two vectors is larger than this, we
// consider them aligned
const float COS_THRESHOLD = 0.999;
#INSERT get_gl_Position.glsl
@ -63,7 +65,7 @@ void create_joint(
vec3 static_c1,
out vec3 changing_c1
){
if(cos_angle > (1.0 - ANGLE_THRESHOLD) || int(joint_type) == NO_JOINT){
if(cos_angle > COS_THRESHOLD || int(joint_type) == NO_JOINT){
// No joint
changing_c0 = static_c0;
changing_c1 = static_c1;
@ -161,9 +163,8 @@ void main() {
vec3 v01 = normalize(p1 - p0);
vec3 v12 = normalize(p2 - p1);
float angle = acos(clamp(dot(v01, v12), -1, 1));
is_linear = float(abs(angle) < ANGLE_THRESHOLD);
float cos_angle = v_joint_product[1].w;
is_linear = float(cos_angle > COS_THRESHOLD);
// If the curve is flat, put the middle control in the midpoint
if (bool(is_linear)) p1 = 0.5 * (p0 + p2);